AB Science — Capital/Financing Update 2016

Apr 17, 2016

NOT FOR DISTRIBUTION, PUBLICATION, RELEASE, DIRECTLY OR INDIRECTLY, IN THE UNITED STATES, CANADA, AUSTRALIA OR JAPAN

REGULATED INFORMATION FOR IMMEDIATE RELEASE

AB SCIENCE LAUNCHES A SHARE CAPITAL INCREASE BY WAY OF ACCELERATED BOOK BUILDING

• Net proceeds to be used to fund the Company's general needs and to finance its clinical development program
• Book-building process to begin immediately

Paris, France – April 17, 2016 ; 8 am

AB Science S.A. (the « Company » or « AB Science »), NYSE Euronext – FR0010557264 - AB), a pharmaceutical company specialized in research, development and commercialization of protein kinase inhibitors (PKIs) announces today the launch of a capital increase by means of a Private Placement reserved to institutional investors (the « Private Placement »).

The Private Placement is capped at 956,025 shares, to be issued immediately or following the exercise of any instrument giving access to the share capital.

The capital increase will be conducted without the pre-emptive rights of shareholders pursuant to the delegation granted to the board of directors by the AB Science's combined shareholders meeting on June 22, 2015 (12th and 13th resolutions).

AB Science intends to use the net proceeds from the Private Placement for the funding of its general needs and to finance its clinical development program.

The Private Placement will be conducted by way of an accelerated book-building starting immediately at the end of which the number of shares issued and the placement price will be determined.

The placement price will be determined within the limits set by the 13th resolution of the June 22, 2015 AB Science's combined general shareholders' meeting.

In the context of this Private Placement, AB Science has agreed on a right of participation (to the benefit of participants in the Private Placement) for future non-equity line financings for a period of one year.

No public offering will be made in France, the United States of America or any other jurisdiction.

AB Science's share capital

Prior to the Private Placement, AB Science's share capital consists of 35,010,291 ordinary shares.

Expected timetable for the capital increase

The book-building process is to begin immediately.

In compliance with the shareholders' delegation granted to the board of directors by the AB Science's combined shareholders meeting on June 22, 2015 (12th and 13th resolutions), any discount to the issue price of the shares may not exceed 10% of the volume weighted average

price of AB Science shares on Euronext Paris calculated over the five trading days prior to the pricing date.

The final subscription price and number of shares are expected to be announced by AB Science as soon as practicable after the close of the book-building process.

The settlement date, on which the new ordinary shares will be delivered to the investors against payment, is expected to be April 20, 2016.

Application for admission to trading of the new ordinary shares will be made on the regulated market of Euronext Paris under the existing ISIN securities identification code for AB Science ordinary shares.

The Private Placement is not subject to a prospectus to be approved by the French market regulator (AMF) or any other regulatory authority.

The new ordinary shares

The new ordinary shares will be fungible in all respects with AB Science existing ordinary shares.

Public Information

Public Information on AB Science, including its business, financials, perspectives and risk factors on its business, activities, and securities can be found in the Company's annual report and half-year report available, together with other regulated information about the Company, at the Company's website (www.ab-science.com).

Hearing before the commission des sanctions of the French market regulator (AMF)

A hearing is scheduled before the commission des sanctions of the AMF on May 20, 2016.

The AMF investigators raised the following concerns:

• AB Science published early November 2013 press releases reporting on (i) the transformation of its amyotrophic lateral sclerosis (ALS) trial from phase II into phase III; and (ii) a phase III trial into mastocytosis. The investigators expressed concerns that these reports may have been too optimistic and inaccurate.
• AB Science issued 256,000 new shares through its equity line (by way of capital increase) two weeks before the vote of the Committee for Medicinal Products for Human Use (CMPH) of the European Medicine Agency on the masitinib marketing authorization for GIST. AB Science could have had privileged information at the time of the capital increase.

AB Science contests these concerns and the hearing before the commission des sanctions does not prejudge the outcome in any way.

About AB Science

Founded in 2001, AB Science is a pharmaceutical Company specializing in the research, development and commercialization of protein kinase inhibitors (PKIs), a class of targeted proteins whose action are key in signaling pathways within cells. Our programs target only diseases with high unmet medical needs, often lethal with short term survival or rare or refractory to previous lines of treatment in cancers, inflammatory diseases, and central nervous system diseases, both in human and animal health.

AB Science has developed a proprietary portfolio of molecules and the Company's lead compound, masitinib, has already been registered for veterinary medicine in Europe and in the USA. The Company is currently pursuing twelve phase 3 studies in human medicine in first-line and second-line GIST, metastatic melanoma expressing JM mutation of c-Kit, multiple myeloma, metastatic colorectal cancer, metastatic prostate cancer, pancreatic cancer, mastocytosis, severe asthma uncontrolled by oral corticosteroid, Alzheimer's Disease,

progressive forms of multiple sclerosis, and amyotrophic lateral sclerosis. The Company is headquartered in Paris, France, and listed on Euronext Paris (ticker: AB).

Further information is available on AB Science's website: www.ab-science.com.

This press release contains information related to the markets where AB Science operates and forward-looking statements. Even though the Company believes that this information and forward looking statements are based on current plans and forecasts of AB Science, such forward-looking statements are, by their nature, subject to a number of important risks and uncertainties that could cause actual results to differ materially from the plans, objectives and expectations expressed or implied in such forward-looking statements. A full description of the risks and uncertainties that could affect its results, financials, performance or achievements and thus lead to a change from the forward-looking statements, securities can be found in the Company's annual report and half-year report available at the Company's website (www.abscience.com).

Disclaimer

In France, the offer of AB Science shares described above will take place solely as a Private Placement, in accordance with Article L. 411-2 of the French Financial and Monetary Code and applicable regulations. The offering does not constitute a public offering in France, as defined in Article L. 411-1 of the French Financial and Monetary Code.

With respect to Member States of the European Economic Area that have transposed European Directive 2003/71/EC of the European Parliament and European Council (as amended in particular by Directive 2010/73/EU to the extent that the said Directive has been transposed into each Member State of the European Economic Area), no action has been taken or will be taken to permit a public offering of the securities referred to in this press release requiring the publication of a prospectus in any Member State.

This press release and the information it contains does not, and will not, constitute a public offering to subscribe for or sell, nor the solicitation of an offer to subscribe for or buy, shares of AB Science in the United States or any other jurisdiction where restrictions may apply. Securities may not be offered or sold in the United States absent registration or an exemption from registration under the US Securities Act of 1933, as amended and applicable State securities laws. AB Science does not intend to register securities or conduct a public offering in the United States.

This distribution of this press release may be subject to legal or regulatory restrictions in certain jurisdictions. Any person who comes into possession of this press release must inform him or herself of and comply with any such restrictions.

By clicking through to the Company's website, a reader represents that it is not located in the United States or in Canada.

For additional information on AB Science, please contact: AB SCIENCE Financial communication and public relations investors@ab-science.com